RUSKIN — Authorities arrested a Ruskin man early Friday on a charge of murdering his girlfriend.

Alejandro Flores-Sanchez, 25, was arrested about 12:40 a.m. on a charge of second-degree murder. He was being held without bail in the Hills­borough County jail.

The Hillsborough County Sheriff's Office said he killed Angela Tavarez-Caballero, 35, and hid her body in a hole under a porch at 307 SE Fifth Ave.

Flores-Sanchez told authorities he and Tavarez-Caballero got into a fight and that he killed her, officials said.

"He then went to great lengths to conceal her body in the residence," sheriff's Col. Donna Lusczynski said.

He removed some of the porch's plywood floor and cut into a second layer before digging a hole 4 feet deep and placing her body in it, Lusczynski said. He refilled it with dirt and replaced the plywood, she said.

"He then put the washer and dryer over the body. It would have been very difficult to locate that body had he not told us where it was," Lusczynski said.

Flores-Sanchez told authorities where to find the body after they found inconsistencies in his first interview, the Sheriff's Office said.

Officials said one of Tavarez-Caballero's daughters was home during the fight and saw Flores-Sanchez grab her. The girl was told to go to her room, and later saw her mother unresponsive in the living room, authorities said. She was afraid to come forward but later told authorities what she saw.

This is Flores-Sanchez's first arrest in Florida, state records show. The investigation began after Tavarez-Caballero's adult son told authorities Thursday his mother had been missing since Tuesday. Her son said she and her two daughters, ages 6 and 13, were going to move in with him and had planned to meet him Tuesday. Sheriff's officials said she died of a head injury and an autopsy would be done.

Researcher Caryn Baird contributed to this report. Keeley Sheehan can be reached at ksheehan@tampabay.com.